1. Field
The present disclosure relates generally to electric motor systems and, in particular, to controlling electric motor systems. Still more particularly, the present disclosure relates to a method and apparatus for controlling the operation of electric motor units in electric motor systems.
2. Background
An electric motor is a device that converts electrical power into mechanical power. Electric motors are used for various applications. These applications include fans, pumps, tools, disk drives, drills, and other types of devices that may be found in these and other types of platforms. One type of electric motor that has become more commonly used is a brushless electric motor. This type of motor may be operated using direct current.
A brushless electric motor may be controlled through a device such as a microcontroller. A microcontroller may implement control laws to control the operation of the brushless electric motor. In particular, the control laws may be used to increase efficiency and operation of this type of electric motor.
Control laws may become more complicated, larger in number, or both, to obtain a desired efficiency for a brushless electric motor. As control laws become more complicated and larger in number, the microcontroller implementing the control laws also may become more complicated.
For example, a higher density circuit board, a larger circuit board, additional cooling, and changes may be needed. These changes may increase the weight, size, heat generation, energy use, or some combination thereof for the entire electric motor system as a whole. Further, the cooling system needed for additional cooling also uses more energy to cool the controller. As a result, the amount of energy used by the electric motor system also may increase more than desired.
Further, depending on the particular implementation, a more complex microcontroller, more than one microcontroller, or both processing the control laws may be present. As a result, higher density or larger circuit boards may be used to implement the microcontroller.
These more complex microcontrollers also may result in the use of components that have higher costs. As a result, the cost of the electric motor system may increase more than desired as compared to the benefits.
Additional microcontrollers may be used for redundancy in case one microcontroller does not operate as desired. If the second redundancy is not present, incorrectly operating microcontrollers may cause inconsistency in an electric motor that may require maintenance. This maintenance may include repair or replacement of the electric motor.
With the addition of more microcontrollers, additional heat, weight, space, and energy use may occur. These increases may not be feasible for some applications in which one or more of these factors are a concern.
With more complex microcontrollers, the use of additional microcontrollers, or both, cooling systems may become more complex, larger, or both to sufficiently cool the microcontrollers. These cooling systems also may use more energy than desired.
This type of additional redundancy, however, increases weight, size, heat generation, and electricity used. As a result, the type of systems may not be as desirable when lower weight, smaller size, lower heat generation, lower energy use, or some combination thereof is desired.
One solution may involve using materials that may reduce some of these factors. These materials, however, may be more expensive than desired. As a result, these types of electric motor systems may not be usable in different applications where weight, size, heat generation, energy use, or some combination thereof is of concern.
With the use of more complex microcontrollers, these microcontrollers may be more susceptible to electromagnetic interference. Electric motors generate electromagnetic interference that may affect the operation of these types of microcontrollers.
Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.